Chapter 7 Word File - c|net

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The Internet

and Intranets


Briefly describe how the Internet works, including alternatives for connecting to it, and
the role of the TCP/IP protocol


Identify and briefly describe five services associated with the Internet


Describe the World Wide Web, including tools to view and search the Web


Outline the process for creating Web content


Describe Java and discuss its potential impact on the software world


Define the term intranet and discuss how organizations ar
e using intranets


Identify several issues associated with the use of networks

Use and Functioning

of the Internet

The Internet

The world’s largest computer network

Consists of thousands of interconnected networks

ARPANET: Ancestor of the Internet

Started by the Department of Defense to link DOD & military research

Split into two networks

MILNET: all military sites

Reduced ARPANET: non
military sites

The Internet

How the Internet Works


Internet transmits data from one computer (host) to another.

How the Internet Works

Messages are routed through the multiple networks that make
up the Internet by using special protocols.

Internet Protocol (IP)

The set of conventions used to pass packets from one host to another

Transport Control Protocol (TCP)

Used in connection with IP

Operates at the transport layer

How the Internet Works

Each computer on the Internet has an assigned address to
dentify it from other hosts (e.g.,

Most also have names, which are much easier to remember
than the numbers (e.g,

Internet Zones

: commercial sites

: educational sites

: military sites

: government sites

: networking organizations

: organizations

: businesses/firms

: businesses offering goods for purchase

: information service providers

: entities related to World Wide Web activities

: cultural and entertainment activities

: recreational activities

: individuals

Three Ways

to Access the Internet

Connect via LAN server

Connect via SLIP/PPP

Connect via an on
line service

Three Ways

to Access the Internet

Requirements for

Connecting via LAN Server

Network adapter card

Open Datalink Interface (ODI) or Network Driver Interface
Specification (NDIS)



Software that provides a set of communications protocols that
perform the compl
ete functions of the seven layers of the OSI
communications model

A Communications Stack for Accessing the

Requirements for

Connecting via SLIP/PPP

Modem and the TCP/IP protocols

Serial Line Internet Protocol (SLIP) or Point to Point Prot
(PPP) software (communications protocols that transmit packets
over telephone lines, allowing dial
up access to the Internet)

Requirements for Connecting via an On


Standard communications software

line information ser
vice account

Sample On
Line Service

Internet Services

Internet Services

Electronic Mail (E

A way of sending an electronic message between individuals or

Often called a
store and forward

Allows e
mail to be stored until it can be forwarded to the next

Electronic Mail (E

Typical e
mail message includes:

“From” line

“To” line

“Subject” line


Usenet and Newsgroups


A system closely allied wit
h the Internet that uses e
mail to provide a
centralized news service


An on
line discussion group that focuses on a particular topic

Sample Newsgroup:

Sewing Newsgroup

Finding Information and Downloading Files


A terminal emulation protocol that lets a user log on to another
computer on the Internet to gain access to publicly available files

File Transfer Protocol (FTP)

Describes the file transfer process between a host and a remote

Internet Phone

and Videoconferencing Services

Internet phone service

Enables users to communicate with other Internet users around the
world who have compatible equipment and software

Internet videoconferencing

Supports both voice and visual communications

An emerging service

The World Wide Web

World Wide Web

Involves over 30,000 independently owned computers that work
together as one in an Internet Service

Also known as the Web, WWW, or W3

A menu
based system that uses the client/server model

World Wide Web

Data exists on the Web as:

ASCII characters

Word processing files

Audio files

Graphic images

Any other sort of data that is stored in a computer file

World Wide Web

A web site is like a magazine, with a cover page (
e page)

that has graphics, titles, and black and blue text.

: Blue, underlined type which links the on
screen page to
other documents or Web sites


Connects data on pages, allowing users to access topics in any order

World Wide


Uniform Resource Locators (URLs)

A standard way of coding the location of the
Hypertext Markup



Hypertext Transfer Protocol (HTTP)

A set of rules that allows the Web user to retrieves a document

Sample Web Site:

The Wall Street Journal

Sample Web Site:

Center for Disease Control

World Wide Web

Hypertext Markup Language (HTML)

Standard page description language for Web pages

HTML tags

Codes that let the browser know how to format the text

Business Uses of the Web

In 1991, the Commercial Internet Exchange (CIX) Association
was established to allow businesses to fully connect to the

Now businesses use the Internet for many applications:
mail, customer information web sites
, advertising direct sales
web sites, on
line shopping.

Web Browsers

A Web tool that creates a unique, hypermedia
based menu as a
graphical interface to the Web


Small programs embedded in Web pages

Search Engines

Web search tools that help users find the information they seek

Two types of Web search tools

Directories: List of Web sites classified by topic

Indexes: Allow users to find specific documents through keyword

Sample Search Engine

Developing Web Content

Web authors work with several standards to create their pages.

Two main problems limit creativity.

Confusing HTML standards

Slow communications speeds

Virtual Reality Modeling Language (VRML)

A language for creating

D scenes on the Internet


oriented program language from Sun Microsystems
based on C++

Allows small programs (

to be embedded within an
HTML document

Downloading an Applet

from a Web Server

Web Page with a Java Applet


Internal corporate networks built using Internet and World Wide
Web standards and products

Most companies have the foundation for an intranet: a network
that uses the Internet’s TCP/IP.

Next stage of intranet usage: Interactive transac

Common Intranet Uses

Net Issues

Managing the Internet

and Intranets

Although the Internet is a huge, global network, it is managed at
the local level; no centralized governing body controls the

The Internet Society

and the Internet Activities Board (IAB) are
the closest things to centralized governing bodies.

Service Bottlenecks

Primary cause: phenomenal growth in traffic

Other causes

More than half of Web users have slow modems (14.4 Kbps or less)

fficient software and software glitches


The process of converting a message into a secret code and
changing the encoded message back into regular text

Digital Signature

A technique used to meet security needs for the processing of on
financial transactions



A device that sits between the internal network and the outside

Purpose: To limit access into and out of a network based on
an organization’s access policy

Can be set up to allow access from specific hosts and networks
or to prevent access from specific hosts

Information Systems Principles

The Internet is like many other new technologies

it provides a
wide range of ser
vices, some of which are effective and
practical for use today, whereas others are still evolving, and
still others will fade away from lack of use.

Information Systems Principles

People need improved means to communicate and collaborate

thus the pop
ularity of the Internet and other technology and
services that can make this happen.

Information Systems Principles

As with every new technology, the Internet and corporate
intranets are experiencing growing pains. Standards are
needed, options must b
e sorted out, financial transactions must
be made secure, privacy must be guaranteed, and legal issues
must be addressed.

Information Systems Principles

The Java approach to delivering software to users is so radically
different from current approaches that it will drive major
changes in the software industry.

End of Chapter 7